The present invention relates to image processing and, particularly, to an improved system and method for correcting defects in images.
Digitized images often include imperfections that are not present in the original image. One cause of such defects may be the components of the image capturing system. For example, a scanning surface, or platen, may contain scratches and other optical path obstructions. These optical path obstructions are digitized along with the original image and appear as imperfections in the digitized image.
Another cause of imperfections is defects within the physical medium of the image. For example, a photograph, film negative, or other physical medium may be scratched or deformed despite careful handling. In addition, dust, hair, smudges, and the like may be deposited on the surface of the physical medium and will be digitized along with the original image. These defects will also appear in the digitized image as defects.
Conventional software programs are available to identify such defects. Such programs typically create xe2x80x9cbinaryxe2x80x9d defect maps that mark each pixel in the defect map as defective or non-defective. Other programs may also provide xe2x80x9ccontinuousxe2x80x9d defect maps, wherein each pixel is marked with a defect value proportional to the severity of any defect in the pixel.
Once a pixel has been marked as defective, conventional imaging programs replace the defective pixel with a replacement amplitude value determined from amplitudes of the surrounding pixels within a predetermined area. This interpolated value is then used to xe2x80x9cfillxe2x80x9d the defective pixel.
After such automatic image correcting systems have been run, there may remain certain defects which the system cannot correct. Such defects may, for example, be of such amplitude as to result from a hole in the film. Another conventional method of dealing with such defects is to allow the user to manually identify and manually fill in the remaining defective pixels. However, visual inspection can be unreliable, and defective pixels can be overlooked. Conventional defect correction programs thus have several technical disadvantages when applied to heavily damaged images.
These and other drawbacks in the prior art are overcome in large part by a system and method for correcting defects in heavily damaged images according to the present invention. In accordance with one implementation, a secondary defect map, defining heavily damaged portions of the image which were not corrected automatically, is generated. The secondary defect map allows the user to correct the defects by highlighting the uncorrected areas and applying a defect correction process to the uncorrected areas.
Thus, the defect correcting system and method provides an improved method for correcting heavily damaged images by automatically generating a defect map of those defects that are so severe that an automatic defect correction system cannot correct them. The defect correcting system and method then provides the user with various options for correcting the defects. These may include selection of a replacement value from a palette of values, interpolation between values, or stretching or healing across the defect region.